The TokenCancelOperation class is used to cancel tokens in the STS. It implements the CancelOperation interface in the STS provider framework. In addition to the properties that it inherits from AbstractOperation, it has a single property that can be configured:
List<TokenCanceller> tokencancellers - A list of TokenCanceller implementations to use to cancel tokens.
Recall that AbstractOperation uses the RequestParser to parse a client request into TokenRequirements and KeyRequirements objects. TokenCancelOperation first checks that a "CancelTarget" token was received and successfully parsed (if so it will be stored in the TokenRequirements object). If no token was received then an exception is thrown.
The TokenCancelOperation then populates a TokenCancellerParameters object with values extracted from the TokenRequirements and KeyRequirements objects. It iterates through the list of defined TokenCanceller implementations to see if any "can handle" the received token. If no TokenCanceller is defined, or if no TokenCanceller can handle the received token, then an exception is thrown. Otherwise, the received token is cancelled. If there is an error in cancelling the token, then an exception is also thrown. A response is constructed with the context attribute (if applicable), and the cancelled token type.